Enhanced Multicast Broadcast System (EMBS) is a broadcasting system that is offered over existing wireless networks, such as those utilizing GSM, UMTS, or OFDMA. EMBS is known by other names, such as Evolved Multimedia Broadcast Multicast Service, E-MBMS, E-MBS, eMBMS and (e)MBMS. These names can be used interchangeably, and refer to the same transmission system.
EMBS is a point-to-multipoint communication system where data packets are transmitted simultaneously from a single source to multiple destinations. The term broadcast refers to the ability to deliver contents to all users. Radio and television contents are examples of broadcast transmissions. Multicast refers to contents that are directed to a specific group of users that have an associated subscription for receiving such services. For example, a group of users interested in sports or news broadcasts could make up a multicast group. In the cellular context, Mobile TV is one example of a multicast broadcast service. The IEEE 802.16m standard supports enhancements to the multicast broadcast service that will enable operators to provide full triple-play service offerings—telephony, internet and TV—for mobile handheld devices.
To improve user experience, IEEE 802.16m has targeted improvements in the content delivery and efficiency of EMBS. However, currently, there is no detailed standard for carrying out the interaction of EMBS users to EMBS content in E-UTRAN, IEEE 802.16 or UMB. While EMBS happens mainly in downlink, there is significant interest in allowing a mobile station to interact with a base station and the EMBS content server to facilitate bi-directional EMBS communication.